US 7361011 B2
The invention concerns an ejector system, where the ejectors or the stripper plates (10) in the turnable tool part(s) (8) are being activated in turn after each turning and opening/closing cycle in the machinery by means of a stationary placed mechanism (11). This can perform a forward and backwards movement, and is situated outside the turnable mold part(s), but in such a way that the stationary placed forward and backwards going mechanism (11) enables the shifting activations of the ejector mechanism (10) on the different sides of the turnable mold part(s) in turn. The stationary placed forward and backwards going mechanism (11) can perform its movements by hydraulic, pneumatic, electric or other influence of e.g. a piston. The turnable mold parts of the tool suitably turn around axis, which are parallel and at a right angle on the opening/closing movement of the tool. At a right angle at this axis is each turnable mold part preferably designed with a cross section, which makes up a regular polygon, preferably a square.
1. An ejector comprised of:
a frame, which holds a plurality of mold parts, each mold part being used for molding a work piece, the mold parts having cavities in which work pieces are molded, each mold part having a top and a bottom and being attached to and rotating with an axle having a center axis about which each axle and each corresponding mold part rotates
within the frame, the mold parts being arranged so that that cavities of the mold parts face away from the axle;
an ejector mechanism coupled to the frame and located substantially between the axle and at least one of the plurality of mold parts, the ejector mechanism being comprised of first and second ejection arms, which are sized, shaped and arranged to move transversely relative to the axis of the axle, a rotation of the mold parts around the axle by ninety degrees positions a first mold part in a first position whereat a work piece in said first mold part can be ejected after a second mold part is closed to form a second work piece in said second mold part, whereat transverse motion of the ejection arms toward the first mold part causes the first work piece in the first mold part to be ejected from the first mold part's cavity, said first and second ejection arms acting at the top and bottom of the second mold part; and
wherein a second work piece to be molded in a second mold part is ejected from the second mold part after the first work piece is ejected from the first mold part; and
wherein subsequent rotations of the mold parts by ninety degree increments about the axis locates one of them into said first position and another of them into said second position.
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The invention concerns a procedure for the ejection of objects placed on (a) turnable mold part(s) in a tool preferably for plastic parts as described in the introduction of claim 1 as well as a machinery for the exercise of the procedure.
There are known a series of different procedures for the molding of plastic objects and ejection hereof in a tool or mold, which is equipped with at least one turnable mold part. An example hereof is the in my international patent application No. WO 98/35808; described procedure and machinery for the production of two- or multi component objects of plastic. In this application is also mentioned a special ejector system in the turnable mold part, but working according to another principle than the one mentioned in this application.
In another of my international patent applications No. WO 00/73040 there is also shortly described the possibility to eject plastic objects in a turnable mold part in a tool simultaneous with molding other objects in the tool.
The hitherto described procedures and machinery for the molding/demolding of molded objects however have different disadvantages and flaws. These are attempted to be solved by the procedure and machinery according to this invention. Hereby are also obtained a series of advantages and simplifications of the hitherto known ejector systems, which will be able to reduce the cycle time considerably and consequently the price of the finished objects, as well as reduce the size of the turnable mold part(s) and consequently both the prize of the tool and the running hereof.
The invention is characterized by the fact, that the ejector systems of the turnable mold part(s) (8) is activated in turn(s) after each turning and/or opening/closing cycle in the apparatus by means of a movable ejector mechanism (11) placed on a part of the tool, which is not turnable with the turnable mold part(s) (8), but which enables the changing activations of the ejector mechanisms (10) of the different sides of the respective turnable mold part in turn.
The stationary situated forward- and backward mechanism can perform its movements by hydraulic, pneumatic, electric or other influence from e.g. a piston.
The turnable mold parts of the tool suitably turn around axis, which are parallel and at a right angle to the opening/closing movement of the tool. At a right angle to this axis each turnable mold part is preferably made with a cross section, which constitutes a regular polygon, preferably a square. This square can suitably have its corners cut of, so less opening is required of the mold to turn the middle section around. For the same reason there suitably can be placed two or more turnable mold parts side by side in the tool. Besides a square or an adjusted square the cross section can be built like a regular hexagon, octagon or another preferably regular polygon, where the two opposite sides are parallel to each other.
The different uses and advantages by the procedure and mechanism according to the invention is further mentioned under the description to the drawing, where
The on the drawing shown is only an example of how this invention can be realized in working tools. A number of other embodiments can be thought of the ejector system according to the invention, but the shown should be sufficient to show the fundamental principles of the invention.
On the drawing are exclusively shown ejector systems in one-component molding molds, but the system is at least as applicable in two- or more-component molds.
Besides the shown embodiments of the ejector system there also could have been shown one or more examples on different ways where the ejectors in the ejector system can be designed to be able to demold special objects. Here is e.g. thought upon the common ejector pins, tube ejectors, as well as various combinations, where air or other kinds of help are used to obtain an optimal ejection of the objects from the turnable mold part in the tool. In a special version, that also is not shown on the drawing, there can be jaws in a stationary position, which enter and grasp around the objects and pull the objects off the turnable mold part and/or activates an ejector system in the turnable mold part. Hereby very complex and/or critical objects will be able to be handled further in a robot movement, and thereby enable automate of objects otherwise hardly possible to eject/demold in a traditional way.
Finally shall be mentioned an example of a horizontal and/or vertical turning table with an according to the invention integrated ejector system, which in many different tools can be used to activate and work the ejector system, which is prepared to use such an ejector system. This at the same time as the turnable mold part(s) in these tools could be monitored and turned by the driving unit in this turning table, which would give great savings in the tool costs, as you whether should have to built a turning unit or an ejector unit into the turnable mold parts.
Furthermore there can be imagined other ways to activate the ejector system according to the invention, e.g. by using the opening and closing movement to activate and work the ejector system according to the invention, possibly in combination with and/or through an activation and mechanical force driven turning of the turnable mold part(s).
The ejector system according to the invention is not limited to be able to eject objects on the side, as the system is functional in all directions from the turnable mold part, as long as the individual mold construction allows it, and not least gives room for this.
In light of the foregoing there is disclosed a procedure and an ejector system for ejecting molded parts from molds. The maids are referred to herein as “mold parts” and they are identified in the figures by reference numeral 8. As described above, parts are formed in the mold parts 8 by molding. As also described above, the molded parts are identified in the figures by reference numeral 9.
The molded parts 9 are ejected from the molds, i.e., the “mold parts 8” by an ejector system that is comprised of a frame 7, in which the mold parts 8 are mounted and by which they are able to turn together around an axle 12. As can be seen in the figures, each of the mold parts 8 faces outwardly and away from the axle 12. As the several mold parts 8 turn around the axle 12, in 90 degree steps or increments, the mold parts 8 come in front of an ejector mechanism by which the molded parts 9 are ejected from a corresponding mold part 8. As stated above, ejector mechanisms 11 are located at both the top and bottom of the mold parts 8.
The ejector mechanisms 11 that eject the molded parts 9 from the mold parts 8, are driven by ejection arms 14, which are in turn driven by oil cylinders 13. The frame 7 and mold parts 8 are configured so that the mold parts 8 can rotate around the axle 12. Each 90-degree rotation of the mold parts 8 about the axle 12, places a different one of the mold parts 8 in position for having its corresponding molded part 9, ejected by the ejector mechanism 11.